Reddish-brown cotton dye.



bene disulfonic acid) UNITED STATES PATENT OFFICE.

AUGUST BLANK AND WLADIMIR RODIONOW, OF L EVERKUSEN, NEAR COLOGNE, GERMANY, ASSIGNORS TO FARBENFABRIKEN VORM. FRIEDR. BAYER 85 CO., 01' ELLBERFELD, GERMANY, A CORPORATION OF GERMANY.

REDDISH-BROWN COTTON DYE.

No Drawing.

To all whom it may concern:

Be it known that we, AUGUST BLANK and VLADIMIR RODIONOW, chemists, citizens of, respectively, Germany and Russia, residing at Lex 'erkusen, near Cologne, Germany, have invented new and useful Improvements in Reddish-Brown Cotton Dyes, of which the following. is a specification.

This application relates to the manufacture and production of'a specific. new dyestufi which can be obtained by treating direct yellow with para-sulfan lic acid-azo-lnaphthylamin while in another application we describe the whole class to which this ..specific dye belongs.

Example: Direct yellow (azoazoxydistiltained by treating 70 parts by'weight of para-n1tro-toluene SlllfOIllQ acid with caustic sodaflye and 28.5 parts of para-sulfauiheacid-azo-l-naphthylamin are stirred up wit-l1 1000 parts of water and 50 parts of a 30 per cent. caustic soda lye to a thin paste.

,Th'e resulting mixture is. then heated to illioiling for about 20 hours in a vessel pro- 'ldedwith a reflux condenser and a stirrer.

-'he solution is neutralized with mineral acid and the dyestuii is precipitated with salt. It is after being dried and pulverized Specification of Letters Patent.

Application filed October 14, 1909. Serial No. 522,619.

(sodium salt) ob- Patented Mar. 1, 1910.

in water with a brown color, soluble in concentrated sulfuric acid with a violet color,

being precipitated in the shape of brown A flakes from such a solution by addition of water; and dyeing unmordanted cotton reddish-brown shades, substantially as described.

In testimony whereof we have hereunto set our hands in the scribing witnesses.

AUGUST BLANK. WLADIMIR RODIONOW.

. lVitnesses:

Or'ro Kome, CHAS. J. WRIGHT.

presence of two subwhich 1 

